P0457 on Ford: How to Diagnose & Fix
Evaporative Emission System Leak Detected (Fuel Cap Loose/Off)
3 Ford models · 3 documented issues · 1 critical · $30-$1,800 repair
P0457 on Ford by model: symptoms, diagnosis and fix
The under-hood evaporative-emissions purge valve on 2010-2011 Fusion/Milan (2.5L DOHC and 3.0L) built on or before 3/4/2011 can stick open or leak, unmetered vapor entering the intake. This lights the MIL and sets a cluster of EVAP and lean/fuel-trim codes, and can cause rough idle or hard starts. It is a documented Ford pattern failure with a related TSB covering the affected build range.
Common Symptoms
- Check engine light on
- Rough idle or stalling
- Hard start after refueling
- Fuel smell
- Failed emissions test
How to Fix
Confirm the purge valve holds vacuum and clicks when energized; replace the stuck/leaking purge valve (inexpensive part). Verify no cracked EVAP hoses, a properly sealing gas cap, and an intact charcoal canister before clearing codes. Smoke-test the EVAP system if large-leak codes persist.
Sources for this issue (1)
The EVAP canister purge valve sticks open, causing difficulty fueling (pump nozzle keeps clicking off), rough idle, and check engine light. Very common on the 1.6L engine.
Common Symptoms
- Gas pump nozzle clicks off repeatedly
- Rough idle after fueling
- Check engine light
- Fuel smell
How to Fix
Replace the canister purge valve (solenoid). Clear codes and verify repair. Check EVAP hoses for cracks.
Sources for this issue (1)
S197 Mustangs from the mid-2000s have a documented pattern of fuel tank cracking or leaking, often near the seam or around the evaporative emissions components. Owners report strong fuel odor in garages, visible dripping after fill-ups, and EVAP-related warning lights. Because the issue involves fuel leakage near the rear of the vehicle, it presents a fire risk and can require full tank replacement.
Common Symptoms
- strong gasoline smell near rear of car
- fuel dripping or wetness around tank area
- check engine light
- fuel smell after refueling
- failed emissions or EVAP test
How to Fix
Inspect the tank shell, seams, filler neck area, and EVAP connections with the tank partially filled and under smoke test if needed. Replace the fuel tank if cracked; also inspect/replace damaged seals, vent valves, and straps as needed. Clear EVAP codes and verify no leaks remain after repair.
Sources for this issue (1)
P0457 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0457 mean on a Ford?
P0457 stands for "Evaporative Emission System Leak Detected (Fuel Cap Loose/Off)." This code means the engine computer detected a large leak in the sealed fuel-vapor (EVAP) system, most often traced to a loose, missing, or poorly sealing gas cap. The EVAP system is supposed to trap gasoline vapors and burn them in the engine instead of releasing them into the air; a big leak lets those vapors escape. It is an emissions-only fault that will not hurt the engine, though it triggers the check-engine light and can cause a faint fuel smell. On Ford it is documented across 3 models: Fusion, Fiesta, Mustang.
What are the most common causes of P0457?
The most common causes of P0457 are: Loose, missing, or improperly tightened fuel cap, Worn or cracked fuel cap seal/gasket, Damaged fuel filler neck or sealing surface, Cracked or disconnected EVAP hose, Stuck-open purge or vent valve, Faulty fuel cap that won't hold pressure, Leaking charcoal canister. The specific cause varies by vehicle.
How much does it cost to fix P0457 on a Ford?
Published repair estimates on Ford range from $30 to $1,800 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0457 on a different make?
View P0457 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.